Thiosulfate polymers

ABSTRACT

A thiosulfate polymer includes both an electron-accepting photosensitizer component and thiosulfate groups in the same molecule, arranged in random order along the backbone. The thiosulfate polymer composition can be formulated into compositions and applied to various articles, or used to form a predetermined polymeric pattern after photothermal reaction to form crosslinked disulfide bonds, removing non-crosslinked polymer, and reaction with a disulfide-reactive material. Such thiosulfate polymer compositions can also be used to sequester metals in nanoparticulate form, and as a way for shaping human hair in hairdressing operations.

RELATED APPLICATIONS

This is a Continuation-in-part of U.S. Ser. No. 13/847,063 filed Mar.19, 2013, the contents of which are incorporated herein by reference intheir entirety.

U.S. Serial No. 14/______, filed on even date herewith by Shukla, Mis,and Meyer, which is a Continuation-in-part application of U.S. Ser. No.13/846,985, filed on Mar. 19, 2013.

U.S. Serial No. 14/______ filed on even date herewith by Shukla,Donovan, and Mis, which is a Continuation-in-part application of U.S.Ser. No. 13/847,031, filed on Mar. 19, 2013.

U.S. Serial No. 14/______ filed on even date herewith by Shukla andDonovan, which is a Continuation-in-part application of U.S. Ser. No.13/847,049, filed on Mar. 19, 2013.

U.S. Serial No. 14/______ filed on even date herewith by Shukla,Donovan, and Dirmyer, which is a Continuation-in-part application ofU.S. Ser. No. 13/847,083, filed on Mar. 19, 2013.

FIELD OF THE INVENTION

This invention relates to novel thiosulfate polymers having thiosulfategroups and electron-accepting photosensitizer components in the samepolymer molecule.

BACKGROUND OF THE INVENTION

Alkylthiosulfates (R—S—SO₃ ⁻Na⁺), known as Bunte salts, have been knownfor a long time [Bunte, H. Chem. Ber. 1874, 7, 646]. These salts arereadily prepared by reacting alkylhalides with sodium thiosulfate.Extensive reviews on the preparation and classical reactions of Buntesalts have appeared in the literature (for example, Milligan, B.; Swan,J. M. Rev. Pure Appl. Chem. 1962, 12, 72).

Much of the useful chemistry of Bunte salts results from the potentialof the sulfite moiety to leave the molecule. Small molecule Bunte saltshave various uses. For instance they can be used as insecticides orfungicides, radiation protecting agents (for example as described inU.S. Pat. No. 5,427,868 of Bringley et al.), and paint additives.

Polymeric Bunte salts and Bunte salt derivatives have been used forsetting hair as described in U.S. Pat. No. 5,071,641 (Lewis) and U.S.Pat. No. 5,424,062 (Schwan et al.).

Water-soluble polymers formed from thiosulfate salts are useful in avariety of applications including their use to crosslink or otherwisemodify the properties of natural materials such as wool fibers,cellulosic fibers, and leathers, and as water-insoluble polymeric sulfurdyes. These water-soluble polymers are also used in the coatingindustry.

Bunte salts are commonly reduced to corresponding thiols either bydecomposition with mineral acids or by treatment with reducing agentssuch as NaBH₄, dithioerythritol, or mercaptoethanol. In addition, Buntesalts can be decomposed to disulfides at moderate temperatures. In solidstate, Bunte salts are known to decompose upon heating to formdisulfides, a feature that has been used as thermally switchable imagingmaterials in printing plates. By “switchable” is meant that the polymeris rendered from hydrophilic to relatively more hydrophobic, or fromhydrophilic to relatively more hydrophobic, upon exposure to heat. Forexample, U.S. Pat. No. 5,985,514 (Zheng et al.) and U.S. Pat. No.6,465,152 (DoMinh et al.) describe lithographic printing plateprecursors that are composed of thiosulfate containing polymers, whichupon exposure to IR radiation are crosslink as the thiosulfate groupsare decomposed.

Bunte salts can be used to synthesize disulfides by oxidation [Affleck,J. G.; Dougherty, G. J. Org. Chem. 1950, 15, 865. and Milligan, B. L.;Swan, L. M. J. Chem. Soc. 1962, 2172], acidic hydrolysis [Kice, J. L. J.Org. Chem. 1963, 28, 957], or alkaline degradation [Alonso, M. E.;Aragon, H. Org. Synth. 1978, 58, 147]. Disulfides also can be formedfrom Bunte salts electrochemically [Czerwinski, A.; Orzeszko, A.;Kazimierczuk, Z.; Marassi, R.; Zamponi, S. Anal. Lett. 1997, 30, 2391].This method has been extended to form polydisulfides from “double” Buntesalts, that is, molecules carrying two thiosulfate groups, usingelectrochemistry with gold electrodes [Nann, T.; Urban, G. A. J.Electroanal. Chem. 2001, 505, 125].

In all these noted methods, the Bunte salts are either decomposed byheating or electrochemically in solution, or at high pH. No efficientphotochemical method to decompose Bunte salts is known. Morespecifically, a simple method for patterning thin films using Bunte saltpolymers is not known and would be desirable for various purposes.

It would be very desirable to have more efficient thiosulfate polymersthat can be decomposed photochemical means using a photochemicalelectron transfer process (also known as photoinduced electron transfer)for various uses.

SUMMARY OF THE INVENTION

The present invention provides a non-crosslinked polymer comprising, inrandom order, (a) recurring units comprising pendant thiosulfate groups,and (b) recurring units comprising an electron-accepting photosensitizercomponent covalently attached to the polymer backbone. Suchnon-crosslinked polymer can be used in various thiosulfate polymercompositions and methods described herein, but the compositions andmethods of this invention can be used with different thiosulfatepolymers incorporated therein.

In still other embodiments, a polymer comprises recurring unitscomprising pendant groups comprising both an electron-acceptingphotosensitizer component group and a thiosulfate group. Such polymerscan also comprise additional recurring units that do not containthiosulfate groups or electron-accepting photosensitizer groups, asdescribed below.

Thus, the present invention also provides a non-crosslinked thiosulfatepolymer comprising thiosulfate groups and electron-acceptingphotosensitizer component arranged in the same recurring units.

Moreover, this invention also provides a thiosulfate polymer comprisinga polyester, polyamide, polyurethane, polycarbonate, or polyetherbackbone and pendant thiosulfate groups.

The present invention provides a novel thiosulfate polymer fordecomposing by photochemical electron transfer means. For example, thethiosulfate polymer of the present invention can be used to providepatterns by decomposing polymeric Bunte salts using a photochemicalelectron transfer (also called photoinduced electron transfer) process.In addition, the thiosulfate polymer of the present invention can beused to provide negative working photoresists comprising a Bunte saltpolymer and a photoactivated electron acceptor, and the surface energyof the photoresist can be modified. Other methods can be used to obtainconductive or non-conductive metal coatings after photochemical reactionof the novel thiosulfate polymers.

Many advantages of this invention are achieved using the novelthiosulfate polymers in the presence of electron-acceptingphotosensitizer components. The electron-accepting photosensitizercomponents are covalently attached to the thiosulfate polymer backbone.The electron-accepting photosensitizer components can be selected toprovide sensitivity to any desired spectral absorption.

The thiosulfate polymers of this invention are light sensitive and canprovide light sensitive imaging layers, which when exposed to actinicradiation (generally less than 750 nm) the exposed regions are renderedinsoluble, thereby providing a pattern that can be used for a variety ofpurposes such as surface energy modulation or electroless metal plating.

The present invention provides at least the following advantages:

1. This invention can be used in a photo-initiated electron transferreaction in the solid thiosulfate polymer that creates changes in thesolubility of the material. Because the invention can be used withphotoinitiated electron transfer rather than thermal decomposition,resolution of resulting patterns is much greater.

2. The stable thiosulfate polymer of this invention can be convenientlyfabricated into films, slabs, discs, and other solid forms. In addition,the thiosulfate polymers can be incorporated into porous or non-porouspolymeric particles and such particles can be provided and used asdispersions or emulsions, or provided as coatings.

3. The solubility changes in the thiosulfate polymer of the inventionare large, permanent, localized, and can easily be detected, forming thebasis for patterning.

4. Covalent attachment of the electron-accepting photosensitizercomponent to the thiosulfate polymer backbone (as opposed to simplydissolving the component in the thiosulfate polymer to form a solidsolution) allows for the incorporation of much higher effectiveconcentration of such electron-accepting photosensitizer componentswithout problems associated with phase separation such ascrystallization. Higher concentrations of the electron-accepting photosensitizer component lead to desirable increases in changes inphotochemical sensitivity, thereby improving the performance of thethiosulfate polymer composition and resulting coatings. In addition, thepermanence of recorded information in the resulting patterns is improveddue to low mobility of high molecular weight structures.

5. Coatings of the thiosulfate polymers of this invention can be used tomodulate surface characteristics such as changing part (pattern) or allof a surface from a hydrophilic nature to a hydrophobic nature.

One purpose of the present invention is to provide a thiosulfate polymerand a photosensitive resin composition containing it, which afterexposure to light, undergoes a reaction that generates organicfunctionalities that could be used for absorption of various metals.These resulting metal centers are suitable for electroless metalplating. Thus, the thiosulfate polymer of the present invention providesfor the formation of a conducting layer selectively on a resin patternby coating the thiosulfate polymer composition on a substrate, followedby exposure to suitable radiation, development, and deposition of metalnanoparticles or wires. By using a method described herein, a conductivelayer with a high adhesive strength, which can be similar to theadhesive strength obtained through sputtering, can be obtained at a lowcost through large-scale production.

Compared to known electroless metal plating processes, the methoddescribed herein is very simple and does not require complicatedmonitoring and management of all agents. In addition, the method doesnot require a pilot line and the thiosulfate polymer composition layercan be formed on the substrate through a stable process suitable forlarge-scale production.

The thiosulfate polymer of the present invention can be used to provideletterpress printing plates, flexographic printing plates, offsetprinting plates, graphic arts films, proofing materials, photoresists,circuit board resists, and stereolithographic materials.

DETAILED DESCRIPTION OF THE INVENTION Definitions

As used herein to define various components of the compositions andlayers, unless otherwise indicated, the singular forms “a”, “an”, and“the” are intended to include one or more of the components (that is,including plurality referents).

Each term that is not explicitly defined in the present application isto be understood to have a meaning that is commonly accepted by thoseskilled in the art. If the construction of a term would render itmeaningless or essentially meaningless in its context, the termdefinition should be taken from a standard dictionary.

The use of numerical values in the various ranges specified herein,unless otherwise expressly indicated otherwise, are considered to beapproximations as though the minimum and maximum values within thestated ranges were both preceded by the word “about”. In this manner,slight variations above and below the stated ranges can be used toachieve substantially the same results as the values within the ranges.In addition, the disclosure of these ranges is intended as a continuousrange including every value between the minimum and maximum values.

Under otherwise indicated herein, the terms “non-crosslinked thiosulfatepolymers”, “copolymer”, “polymer”, “thiosulfate polymer”, “polymerhaving thiosulfate groups”, “polymer having Bunte salt moieties”, and“Bunte salt polymer” are considered to be the same in the description ofthe present invention.

A “thiosulfate” group is a substituent defined by the followingStructure I.

Any compound bearing this thiosulfate group is called a “thiosulfatecompound.” When the thiosulfate group is attached to an organic moiety,the resulting compound is an “organic thiosulfate” or Bunte salt. Ifthis organic thiosulfate is a polymer (having a molecular weight of atleast 1,000), the compound is considered a thiosulfate polymer.

Unless otherwise indicated herein, the terms “composition”, “thiosulfatepolymer composition”, and “thiosulfate polymer containing composition”are intended to be the same in the description of the present invention.

Thiosulfate Polymers

In their simplest form, the thiosulfate polymers of the presentinvention can be generally represented by the formula R—S—SO₃M, whereinR represents a suitable polymeric backbone, and M is a suitable cation.

When R is a polymer backbone, it can have multiple —S—SO₃M groupsdistributed randomly or in blocks of recurring units along the chain ofatoms forming the polymer backbone. Useful polymers that provide thebackbone are described in most detail below. The thiosulfate polymerscan be formed as vinyl polymers from ethylenically unsaturatedpolymerizable monomers using or emulsion or suspension polymerizationtechniques, or they can be condensation polymers formed usingappropriate reactive precursor compounds (for example diols with diacidsto form polyester or diamines with diols to form polyamides).

M is hydrogen or a suitable monovalent cation such as a metal cation oran organic cation including but not limited to, an alkali metal ion(lithium, sodium, potassium, and cesium), ammonium, pyridinium,morpholinium, benzolium, imidazolium, alkoxypyridinium, thiazolium, andquinolinium cations. Divalent cations can be present in small amounts sothat premature crosslinking of the thiosulfate polymer is minimized.Thus, in most embodiments, M is a monovalent cation such as potassiumion or sodium ion.

The thiosulfate polymers of this invention can be vinyl polymers derivedat least in part from methacrylate or acrylate ethylenically unsaturatedpolymerizable monomers (known herein as “polymethacrylates” and“polyacrylates”, including both homopolymers and copolymers),polyethers, polyvinyl esters, and polystyrenes (including homopolymersand copolymers derived from styrene and styrene derivatives having oneor more substituents on the pendant benzene ring or attached along thepolymer backbone). Such thiosulfate polymers have an entirely carbonbackbone. However, pendant thiosulfate groups can be incorporated intocondensation polymers including but not limited to, polyesters,polyamides, polyurethanes, polycarbonates, polymers derived fromcellulose esters, and polysiloxanes using chemistry that would bereadily known to one skilled in the art.

The thiosulfate polymers of this invention need not be mixed with anelectron-accepting photosensitizer component as in other thiosulfatepolymer compositions, but the electron-accepting photosensitizercomponent is incorporated into the thiosulfate polymer so that thethiosulfate polymer includes both types of pendant groups (thiosulfategroups and electron-accepting photosensitizer components). In addition,the thiosulfate polymers can be designed so that the same recurringunits comprise pendant groups that comprise both electron-acceptingphotosensitizer groups and thiosulfate groups. Representativethiosulfate polymers of this invention are described below in theThiosulfate Polymer Examples.

In general, the thiosulfate polymers are optically transparent in thespectral region where the electron-accepting photosensitizer componentabsorbs. That is, the thiosulfate polymer should not have significantabsorption at the excitation wavelengths, and should not interfere withthe chemical transformation of the thiosulfate moieties. The thiosulfatepolymers can be linear, branched, or dendritic in form.

The thiosulfate polymers generally have a molecular weight (M_(n)) of atleast 1,000 and up to and including 1,000,000, or typically at least10,000 and up to and including 100,000, as determined using sizeexclusion chromatography (SEC).

The thiosulfate polymers can also have a glass transition temperature(T_(g)) of at least 20° C. and up to and including 250° C. or at least50° C. and up to and including 150° C., as determined using DifferentialScanning calorimetry (DSC).

In such polymers, a thiosulfate group or moiety can be represented bythe following Structure II:

wherein X is a suitable divalent linking group that is attached to apolymer backbone, and M is a cation as defined above.

Useful X divalent linking groups in Structure (II) include but are notlimited to, —(COO)_(n)—(Z)_(m)— wherein n is 0 or 1 and m is 0 or 1. Zcan be a substituted or unsubstituted divalent aliphatic group having 1to 6 carbon atoms including alkylene groups (such as methylene,ethylene, n-propylene, isopropylene, butylenes, 2-hydroxypropylene and2-hydroxy-4-azahexylene), which divalent aliphatic group can compriseone or more oxygen, nitrogen or sulfur atoms in the chain (such ascarbonamido, sulfonamide, alkylenecarbonyloxy, ureylene, carbonyloxy,sulfonyloxy, oxy, dioxy, thio, dithio, seleno, sulfonyl, sulfonyl, andimido), a substituted or unsubstituted arylene group having 6 to 14carbon atoms in the aromatic ring (such as phenylene, naphthalene,anthracylene, and xylylene), a substituted or unsubstituted combinationof alkylene and arylene groups such as substituted or unsubstitutedarylenealkylene or alkylenearylene groups having at least 7 and to andincluding 20 carbon atoms in the chain (such as p-methylenephenylene,phenylenemethylenephenylene, biphenylene, andphenyleneisopropylene-phenylene), or a heterocyclic ring (such aspyridinylene, quinolinylene, thiazolinylene, and benzothioazolylene). Inaddition, X can be a substituted or unsubstituted alkylene group, asubstituted or unsubstituted arylene group, in a substituted orunsubstituted arylenealkylene group or alkylenearylene group, having thesame definitions as Z. It is advantageous to covalently attach both athiosulfate group and an electron-accepting photosensitizer group in thesame pendant group in a single recurring unit. Thus, in Structure II, Xcan be or be derived from an electron-accepting photosensitizercomponent as described below.

As the thiosulfate group is generally located pendant to the polymerbackbone, it can be part of an ethylenically unsaturated polymerizablemonomer that can be polymerized using conventional techniques to formvinyl homopolymers of the thiosulfate-containing recurring units, orvinyl copolymers when copolymerized with one or more additionalethylenically unsaturated polymerizable monomers. A thiosulfate polymercan include more than one type of recurring unit containing thiosulfategroup as described herein. For example, the thiosulfate polymers cancomprise different recurring units derived from different ethylenicallyunsaturated polymerizable monomers. Alternatively, the thiosulfatepolymer can be have the same or different backbone in each recurringunit, but comprise different thiosulfate groups as defined by differentX (with different “n”, “m”, or Z groups) as noted above for Structure(II).

In embodiments of the thiosulfate polymers that are vinyl polymers, thethiosulfate-containing recurring units generally comprise at least 1 mol% of all recurring units in the thiosulfate polymer, or typically atleast 15 mol % and up to and including 90 mol %, or even up to andincluding 100 mol % of all recurring units. In most embodiments, thethiosulfate-containing recurring units comprise at least 15 mol % and upto and including 90 mol % of the total recurring units in thethiosulfate polymer. The recurring units comprising anelectron-accepting photosensitizer component can comprise at least 10mol % and up to and including 85 mol % of the total recurring units inthe thiosulfate polymer. The vinyl thiosulfate polymers can alsocomprise recurring units can be derived from one or more ethylenicallyunsaturated polymerizable monomers including but not limited tomethacrylates, acrylates, acrylamides, methacrylamides, styrene and itsderivatives, vinyl ethers, vinyl esters, (meth)acrylonitrile, vinylpyrrolidones, maleimides, vinyl imidazoles, and vinyl formamide. Askilled polymer chemist would be able to choose suitable co-monomers tobe used to make desired thiosulfate copolymers within the spirit of thepresent invention. The amount of recurring units derived from theseadditional ethylenically unsaturated polymerizable monomers can be atleast 10 mol % and up to and including 80 mol %, or more likely at least20 mol % and up to and including 50 mol %, based on the total recurringunits in the thiosulfate polymer. In general, in the thiosulfatepolymers of this invention, the various recurring units are arranged inrandom order along the polymer molecule, although blocks of certainrecurring units can be arranged if desired.

Thiosulfate polymers of the present invention can be prepared in severalways using understanding and reactants available to a skilled polymerchemist. For example, the useful thiosulfate monomers and reactiveethylenically unsaturated polymerizable co-monomers can be obtained froma number of commercial sources or readily prepared.

For example, thiosulfate-containing ethylenically unsaturatedpolymerizable monomers can be prepared from the reaction between analkyl halide and thiosulfate salt as described in the seminal teachingof Bunte, Chem. Ber. 7, 646, 1884. Thiosulfate polymers can be preparedeither from functional ethylenically unsaturated polymerizable monomersor from preformed polymers having requisite reactive groups. Forexample, if the functional ethylenically unsaturated polymerizablemonomer is a vinyl halide polymer, the functional vinyl polymerizablemonomer can be prepared as illustrated as follows:

wherein R₁ is hydrogen or a substituted or unsubstituted alkyl groupcomprising 1 to 10 carbon atoms or an aryl group, Hal represents ahalide, and X represents a divalent linking group as defined above. Theconditions for these reactions are known in the art.

Thiosulfate polymers of this invention can also be prepared frompreformed polymers in a similar manner as described in U.S. Pat. No.3,706,706 (Vandenberg) as illustrated as follows, the disclosure ofwhich is incorporated herein by reference for the polymer syntheticmethods:

wherein A represents the polymer backbone, Hal represents a halide, andX represents a divalent linking group as described above.

In addition, thiosulfate polymers can be prepared using the reaction ofan alkyl epoxide (on a preformed polymer or a functional monomer) with athiosulfate salt, or between an alkyl epoxide (on a preformed polymer ofa functional monomer) and a molecular containing a thiosulfate moiety(such as 2-aminoethanethiosulfuric acid), as illustrated by Thames,Surf. Coating, 3 (Waterborne Coat), Chapter 3, pp. 125-153, Wilson et al(Eds.) and as follows:

wherein R represents a substituted or unsubstituted alkyl or arylgroups. The conditions for these reactions are known in the art andrequire only routine experimentation to complete.

The thiosulfate polymers further comprise an electron-acceptingphotosensitizer component that is a covalently-connected component. Inother words, the electron-accepting photosensitizer component can beanother group that is incorporated within the thiosulfate polymer, forexample as a pendant group connected to the polymer backbone using asuitable linking group, in some recurring units of the thiosulfatepolymer, or as part of the same recurring unit comprising thethiosulfate groups.

For example, useful linking groups can be any aliphatic or hydrocarbonlinking group that does not adversely affect the usefulness of thethiosulfate polymer. Such linking groups include but are not limited to,—(COO)_(n)(Z)_(m)— wherein n is 0 or 1, m is 0 or 1, and Z is asubstituted or unsubstituted alkylene group having 1 to 6 carbon atoms(such as methylene, ethylene, n-propylene, isopropylene, butylenes,2-hydroxypropylene and 2-hydroxy-4-azahexylene) that can have one ormore oxygen, nitrogen or sulfur atoms in the chain, carbonamido[—C(═O)—NH—], sulfonamide [—SO₂—NH—], a substituted or unsubstitutedarylene group having 6 to 14 carbon atoms in the aromatic ring (such asphenylene, naphthalene, anthracylene and xylylene), or a substituted orunsubstituted arylenealkylene (or alkylenearylene) group having 7 to 20carbon atoms in the chain (such as p-methylenephenylene,phenylenemethylenephenylene, biphenylene andphenyleneisopropylenephenylene). In addition, the linking group can bean alkylene group, an arylene group, vinylenecarbonyloxy[—CR═CR′—C(═O)—O—] wherein R and R′ are independent hydrogen, methyl, orethyl, acetylimino [CH₃C(═O)—N<], alkylenecarbonyloxy [for example,—CH═CH—CH₂—C(═O)—O—], alkyleneimino (for example, —CH₂—NH—),alkylenecarbonyloxy [for example, —CH₂—C(═O)—O—], benzylene,carbonyldioxy [—O—C(═O)—O—], diazo [—N═N—], and ureylene[—NH—C(═O)—NH—].

For example, the linking group can be a substituted or unsubstituteddivalent organic linking group that can have least one oxygen, sulfur,or nitrogen heteroatom in the organic linking group chain. For example,useful Z groups include but are not limited to, carbonyloxy [—C(═O)—O-],sulfonyloxy [—SO₂—O—], oxy (—O—), dioxy (—O—O—) thio (—S—), dithio(—S—S—), seleno (—Se—), sulfonyl (—SO—), sulfonyl (—SO₂—), carbonamido[—C(═O)—NH—], sulfonamide [—SO₂—NH—], substituted or unsubstitutedarylene (such as substituted or unsubstituted phenylene), substituted orunsubstituted cycloalkylene having 5 to 8 carbon atoms in the chain(such as pentylene, 1,3-hexylene, 1,4-hexylene, and3-methyl-1,4-hexylene), imido (—NH—), vinylenecarbonyloxy[—CR═CR′—C(═O)—O—] wherein R and R′ are independent hydrogen, methyl, orethyl, acetylimino [CH₃C(═O)—N<], alkylenecarbonyloxy [for example,—CH═CH—CH₂—C(═O)—O—], alkyleneimino (for example, —CH₂—NH—),alkylenecarbonyloxy [for example, —CH₂—C(═O)—O—], benzylene,carbonyldioxy [—O—C(═O)—O—], diazo [—N═N—], and ureylene[—NH—C(═O)—NH—]. Combinations of two or more of the linking groups canbe used to form a divalent linking group.

For example, the thiosulfate polymer of this invention can be acopolymer comprising, in random order: (a) recurring units comprisingthiosulfate groups (as defined in more detail above), and (b) recurringunits comprising the electron-accepting photosensitizer component thatis derived from an electron-accepting photosensitizer compound, forexample such as one of PS-1 through PS-28 described below.

The relative amount of the (a) and (b) recurring units can varyconsiderably, but in general, (a) recurring units comprise at least 1mol % and up to and including 99.9 mol % of the total thiosulfatepolymer recurring units, and the (b) recurring units comprise at least0.01 mol % and up to and including 99 mol % of the total thiosulfatepolymer recurring units. More typically, the (a) recurring unitscomprise at least 10 mol % and up to and including 75 mol % of the totalthiosulfate polymer recurring units, and the (b) recurring unitscomprise at least 25 mol % and up to and including 90 mol % of the totalthiosulfate polymer recurring units.

Such copolymers can further comprise, in random order: (c) recurringunits other than the (a) and (b) recurring units. Such (c) recurringunits can be derived from one or more ethylenically unsaturatedpolymerizable monomers as described above, which would be readilyapparent to a skilled worker in the art, and such (c) recurring unitscan be present in an amount of at least 0.1 mol % and up to andincluding 50 mol % based on the total recurring units in the thiosulfatepolymer, while the (a) recurring units can be present in an amount of atleast 10 mol % and up to and including 50 mol %, and the (b) recurringunits can be present in an amount of at least 10 mol % and up to andincluding 50 mol %, all based on the total recurring units in thethiosulfate polymer.

In some embodiments, one or more of the additional (c) recurring unitscan comprise a pendant charged group, that is, either negative-chargedand positive-charged groups. In particular embodiments, the additional(c) recurring units comprise a pendant carboxy, carboxylate, phospho,phosphonate, phosphate, sulfo, sulfonate, or sulfite group, orcombinations of such groups in the same recurring units.

In other embodiments, the (c) recurring units are present in thecopolymer with the (a) and (b) recurring units, in an amount of up toand including 50 mol %, the (a) recurring units are present in thecopolymer in an amount of at least 1 mol %, and the copolymer furthercomprises (d) recurring units that have a total neutral charge and arepresent in an amount of at least 1 mol % and up to and including 49 mol%, based on the total copolymer recurring units.

In such embodiments, the molar ratio of the (a) recurring units to the(d) recurring units in the copolymer can be from 1:3 to 3:1.

In still other embodiments, the thiosulfate polymer comprises (a)recurring units comprising thiosulfate groups and (c) recurring unitsthat comprise a pendant charged group in an amount of at least 0.1 mol%, based on the total recurring units in the thiosulfate polymer. The(b) and (d) recurring units can be absent from such embodiments.

Thiosulfate polymers comprising electron-accepting photosensitizercomponents in at least some of the recurring units can be prepared bymethods illustrated below using reactive components and conditions thatwould be readily apparent to one skilled in the art using therepresentative teaching provided below.

Thiosulfate Polymer Compositions

There are various ways to formulate thiosulfate polymer compositions.

The thiosulfate polymer of this invention can be thoroughly mixed withone or more additional electron-accepting photosensitizer components(described below) besides the electron-accepting photosensitizercomponent attached to the polymer backbone. This separate compound(s)can be polymeric or non-polymeric. In other words, theelectron-accepting compound can be a non-polymeric compound, or it canbe attached to a polymer that is not a thiosulfate polymer. Thethiosulfate polymer, with or without an additional electron-acceptingphotosensitizer component, can be supplied as a dry mixture or insolution with one or more suitable solvents, such as tetrahydrofuran(THF), acetonitrile, acetone, methyl ethyl ketone (MEK), dioxane,dimethyl acetamide (DMac), and dimethyl formamide (DMF).

The thiosulfate group is generally present in the thiosulfate polymercomposition in a relatively high concentration. For example, thethiosulfate groups are present in the thiosulfate polymer(s) in thethiosulfate polymer composition to provide at least 10 mol % to andincluding 100 mol % of the recurring units of the thiosulfate polymer.The electron-accepting photosensitizer component can be present in anamount of at least 0.001 weight % to and including 20 weight % based onthe total dry weight of the thiosulfate polymer with the balance of thethiosulfate polymer composition being any optional additives (describedbelow).

As noted above, at least one the electron-accepting photosensitizercomponent is covalently attached to the thiosulfate polymer so that thisthiosulfate polymer has both thiosulfate groups and electron-acceptingphotosensitizer components attached to the polymer backbone as pendantgroups or covalently connected components.

Compounds that can be used as electron-accepting photosensitizercomponents include but are not limited to, metal complexes such ascopper sulfate, copper nitrate, nickel chloride, nickel sulfate, zincacetate, and others that would be readily apparent to one skilled in theart.

In many embodiments, the thiosulfate polymer has a spectral absorptionthat is different than the spectral absorption of either the thiosulfatepolymer group or the electron-accepting photosensitizer component alone.

The electron-accepting photosensitizer component used in the presentinvention initiates the chemical transformation of the thiosulfategroups in the thiosulfate polymer in response to suitable radiation.Thus, the electron-accepting photosensitizer component must be capableof oxidizing the thiosulfate anion to a radical after theelectron-accepting photosensitizer component has absorbed light (thatis, photo-induced electron transfer). In some embodiments, uponabsorption of appropriate actinic radiation, the electron-acceptingphotosensitizer component is capable of accepting an electron from thereactant thiosulfate moiety. In other embodiments, upon absorption ofsuitable actinic radiation, the electron-accepting photosensitizercomponent can be fragmented to provide an oxidant that is capable ofaccepting an electron from the thiosulfate group.

To determine whether a compound is capable of oxidizing the thiosulfategroups in the thiosulfate polymer to provide a radical after thecompound has absorbed light, reaction energetics can be used. There arethree controlling parameters in reaction energetics: (1) the excitationenergy (E_(PS*)), (2) the reduction potential (E_(PS) ^(red)) of theelectron-acceptor photosensitizer component (PS), and (3) the oxidationpotential (E_(R) ^(ox)) of the reactant thiosulfate moiety (R) that isan electron donor. For these reactions to be energetically feasible, theenergy of the excited state should be higher or only slightly lower thanthe energy stored in the primary product, the radical ion pair,PS^(−*)R⁺*.

The excitation energy of the electron-accepting photosensitizercomponent is conveniently determined from the midpoint of the normalizedabsorption and emission spectrum of PS, if the reaction proceeds fromthe singlet excited state. However, if the reaction proceeds via thetriplet state, then the triplet energy of PS should be used as theexcitation energy.

The energy of the radical ion pair, E_(IP), is given by the followingEquation 1, wherein Δ is an energy increment that depends on the mediumpolarity and ranges from nearly zero in highly polar media to about 0.3eV in the least polar media. The oxidation (E_(R) ^(ox)) and reduction(E_(PS) ^(red)) potentials are readily obtained from conventionalelectrochemical measurements in polar solvents such as acetonitrile ormethylene chloride.

E _(IP) =E _(R) ^(ox) −E _(PS) ^(red)+Δ  Equation 1

Polymeric media tend to be low in dielectric constant, and as a resultwould not strongly solvate the radical ion pair. Thus, the energyincrement Δ in Equation 1 is expected to be near the maximum value, thatis, in the range of 0.2 eV to 0.3 eV. Thus, electron-acceptingphotosensitizer components with excitation energy equal to or largerthan the difference between the oxidation potential of the reactant andthe reduction potential of the acceptor, (E_(R) ^(ox)−E_(PS) ^(red)),will satisfy the energetic requirements of photoinitiating the reactionas described in the following Equation 2:

E _(PS*) ≧E _(R) ^(ox) −E _(PS) ^(red)  Equation 2

It is more convenient to express the energetic requirements of theelectron-accepting photosensitizer component relative to the donor interms of a rearranged form of Equation 2 shown below as Equation 3:

E _(PS*) +E _(PS) ^(red) ≧E _(R) ^(ox)  Equation 3

According to Equation 3, for the reaction to be energetically feasible,the algebraic sum of the excitation energy of the electron-acceptingphotosensitizer component and its reduction potential should beapproximately equal to or larger than the oxidation potential of thereactant. When the reactant is the thiosulfate group, which has anoxidation potential of about 1 V (vs. SCE), numerous electron-acceptingphotosensitizer components that meet the requirement of Equation 3, canbe used. Some compounds that meet the requirement of Equation 3 arelisted below in TABLE I.

In general, sum of the electron-accepting photosensitizer componentreduction potential and excitation energy is equal to or greater thanthe oxidation potential of the thiosulfate groups in the thiosulfatepolymer. For example, this sum of reduction potential and excitationenergy can be at least −1 V to and including +5 V (vs SCE), or morelikely of at least −0.1 V to and including +3 V (vs SCE). Reductionpotential and excitation energy can be determined for a given compoundfrom sources in the literature or by measuring these parameters usingcyclic voltammetry and UV-Vis spectrophotometery, respectively.

In general, derivatives from many different compounds can be used aselectron-accepting photosensitizer components for thiosulfate groupreactants, provided that the energetic requirements discussed above (inEquation 3) are satisfied. For example, the electron-acceptingphotosensitizer component can be an organic photosensitizer N-containingheterocyclic compound such as azinium salts, oxyazinium salts,thiazolium salts, pyrylium salts, naphthalene diimides, and naphthaleneimides.

Representative electron-accepting photosensitizer components include butare not limited to, cyano-substituted carbocyclic aromatic compounds orcyanoaromatic compounds (such as 1-cyanonaphthalene,1,4-dicyano-naphthalene, 9,10-dicyanoanthracene,2-t-butyl-9,10-dicyanoanthracene, 2,6-di-t-butyl-9,10-dicyanoanthracene,2,9,10-tricyanoanthracene, 2,6,9,10-tetracyanoanthracene), aromaticanhydrides and aromatic imides (such as 1,8-naphthylene dicarboxylic,1,4,6,8-naphthalene tetracarboxylic, 3,4-perylene dicarboxylic, and3,4,9,10-perylene tetracarboxylic anhydride or imide), condensedpyridinium salts (such as quinolinium, isoquinolinium, phenanthridinium,acridinium salts), and pyrylium salts. Useful electron-acceptingphotosensitizer components that involve the triplet excited stateinclude but are not limited to, carbonyl compounds such as quinones (forexample, benzo-, naphtho-, and anthro-quinones with electron withdrawingsubstituents such as chloro and cyano). Ketocoumarins especially thosewith strong electron withdrawing moieties such as pyridinium can also beused as electron-accepting photosensitizer components. These compoundscan optionally contain substituents such as methyl, ethyl, tertiarybutyl, phenyl, methoxy, and chloro groups that can be included to modifyproperties such as solubility, absorption spectrum, and reductionpotential.

These electron-accepting photosensitizer components can be used asprecursors from which electron-accepting photosensitizer components arederived for covalent attachment to the thiosulfate polymers of thepresent invention, for example in recurring units derived fromethylenically unsaturated polymerizable monomers as described aboveAttachment of the electron-accepting photosensitizer component to thethiosulfate polymer can improve the efficiency of the methods describedherein used for photo-patterning by allowing the thiosulfate componentsand the electron-accepting photosensitizer component to be in closeproximity. In addition, attaching the electron-accepting photosensitizercomponents to the thiosulfate polymer can also reduce insolubility ofthe unattached corresponding components. PS-22 to PS-24 compounds listedbelow in TABLE I are examples of electron-accepting photosensitizercomponents comprising ethylenically unsaturated polymerizable vinylgroups, which components can be incorporated into thiosulfate polymersas described above.

Other useful electron-accepting photosensitizer components are inorganicsalts or complexes such as transition metal salts and complexes, whereinthe metal salts include but are not limited to, copper sulfate, nickelchloride, copper nitrate, zinc acetate, ferric chloride, and others thatwould be readily apparent to one skilled in the art using the teachingherein.

Representative non-polymeric electron-accepting photosensitizercomponents PS-1 to PS-28 are shown in the following TABLE I:

TABLE I PS-1

PS-2

PS-3

PS-4

PS-5

PS-6

PS-7

PS-8

PS-9

PS-10

PS-11

PS-12

PS-13

PS-14

PS-15

PS-16

PS-17

PS-18

PS-19

PS-20

PS-21

PS-22

PS-23

PS-24

PS-25

PS-26

PS-27

PS-28

Thiosulfate polymer compositions described herein can also containoptional ingredients such as a plasticizer, preservative, or surfactant,in individual or cumulative amounts of up to and including 15 weight %,based on total composition weight.

There are various ways to obtain thiosulfate polymer compositions. Thefollowing ways are representative but not meant to be limiting.

1) A thiosulfate polymer can be thoroughly mixed with an additionalelectron-accepting photosensitizer component in an appropriate solventof mixture of solvents.

2) A thiosulfate polymer can be thoroughly mixed with at least 0.1weight % and up to and including 15 weight % of an additionalelectron-accepting photosensitizer component and an equimolar amount ofa tetraalkyl ammonium halide salt in an appropriate solvent or mixtureof solvents. Organic solvents that are soluble in water are useful inthis mixture, including but not limited to tetrahydrofuran, acetone,ethyl methyl ketone, N-methyl pyrrolidone, dimethyl acetamide, andcyclopentanone. The exact amount of electron-accepting photosensitizercomponent depends upon its extinction coefficient and the eventual use.

3) An ethylenically unsaturated ethylenically polymerizable monomercomprising an electron-accepting photosensitizer component can beco-polymerized one or more monomers at least one of which includes therequired thiosulfate group.

4) An ethylenically unsaturated ethylenically polymerizable monomercomprising an electron-accepting photosensitizer component bearingcovalently attached thiosulfate group can be co-polymerized with one ormore ethylenically unsaturated polymerizable monomers.

A useful amount of resulting electron-accepting photosensitizercomponent in the resulting thiosulfate polymer can be at least 0.1 mol %and up to and including 10 mol % in relation to the molar amount ofthiosulfate groups present in the thiosulfate polymer. The exact amountof electron-accepting photosensitizer component depends upon itsextinction coefficient and application. This thiosulfate polymer canalso comprise recurring units derived from other ethylenicallyunsaturated polymerizable monomers having different groups.

In some embodiments, the thiosulfate polymer composition can furthercomprise tetraalkyl ammonium ions including the same or different alkylgroups having 1 to 10 carbon atoms.

In such embodiments, the thiosulfate polymer can be a copolymercomprising, in random order: (a) recurring units comprising thiosulfategroups, (b) recurring units comprising the electron-acceptingphotosensitizer component, and additional (c) recurring units comprisingpendant charged groups.

Articles

The thiosulfate polymer composition can be in the form of aself-supporting slab or disk. It can also be a solution that is appliedto or disposed onto a suitable support or substrate including but notlimited to, polymeric films, glass, metals, stiff papers, or alamination of any of these materials, and the support or substrate canbe formed in any suitable shape. Polymeric film supports can bematerials such as poly(ethylene terephthalate), poly(ethylenenaphthalate), polycarbonate, polystyrene, cellulose acetate, inorganicpolymeric materials such as certain glasses. In some embodiments, thesupport comprises a polyester or glass.

Thus, articles can comprise a substrate having disposed thereon acoating comprising any of the thiosulfate polymer compositions, eitherin a continuous arrangement or in a predetermined pattern.

The support can also be a cylindrical surface and the thiosulfatepolymer composition can be applied to its outer surface. The use of suchcylinders is described for example in U.S. Pat. No. 5,713,287 (Gelbart),the disclosure of which is incorporated herein by reference.

The surface of the support or substrate can be treated in order toimprove the adhesion of the thiosulfate polymer composition thereto. Forexample, the surface can be treated by corona discharge prior toapplying the thiosulfate polymer composition of the present invention.Alternatively, an under-coating or subbing layer, such as a layer formedfrom a halogenated phenol or a partially hydrolyzed vinyl chloride-vinylacetate copolymer, can be applied to the surface of the support prior toapplication of the thiosulfate polymer.

The thiosulfate polymer composition can be applied to the support anddried sufficiently to provide a dry thickness of at least 1 nm and up toand including 1 cm, or of at least 25 nm and up to and including 2000nm. The applied layer can be uniformly over the entire substrate surfacein a continuous or discontinuous manner, and it can be disposed in arandom or predetermined pattern.

Methods of Use

During use of the thiosulfate polymer composition, it is exposed tosuitable radiation (such as UV or visible light) in a predeterminedimagewise fashion, and the thiosulfate polymer composition can beexposed through a mask if desired, and the resulting exposed ornon-exposed regions can be treated in a suitable manner to provideeither a negative-working or positive-working pattern. When using alaser to expose (or image) the thiosulfate polymer composition, a diodelaser is particularly useful because of its reliability and lowmaintenance, but other lasers such as gas or solid state lasers can alsobe used. The combination of power, intensity, and exposure time forlaser imaging would be readily apparent to one skilled in the art.

As noted above, the thiosulfate groups in the thiosulfate polymer arecapable of undergoing a chemical transformation from photochemical oneelectron oxidation, thus causing a change in solubility in the exposedregions of the exposed composition that can be provided on a suitablesubstrate. The photo-induced electron transfer reaction forms a productspecies, a process that defines the cross-linking event. New chemicalbonds are formed between individual reactant moieties that results in adesired change in solubility in the exposed regions.

Scheme I below illustrates the photoinduced electron transfer inducedreaction of the thiosulfate groups in the thiosulfate polymer. After theelectron-accepting photosensitizer component (PS) has absorbedradiation, it oxidizes the thiosulfate ion to form a thiosulfurylradical and an electron-accepting photosensitizer component radicalanion (PS⁻). In a subsequent step, the thiosulfuryl radical (—S—SO₃)fragments to generate a sulfur centered radical (—S) that dimerizes withanother nearby sulfur radical to form a disulfide (—S—S—) bond (SchemeI). When the thiosulfate groups are in the polymer matrix, it isbelieved that the formation of the disulfide (—S—S—) bonds provide thechange in polymer solubility.

With the product formation, besides the change in solubility, changes insurface energy, glass transition temperature, and other opticalproperties such as refractive index and fluorescence properties, canalso occur.

The thiosulfate polymer composition can be applied to a suitablesubstrate using any suitable means such as spray coating, roller orhopper coating, blade coating, spin coating, gravure coating,flexographic printing, or continuous or drop on demand ink jet printing.If the thiosulfate polymer composition comprises a solvent, it can beevaporated or otherwise removed for example at 50° C. to 70° C. using asuitable means such a heater or dryer. The conditions for thiosulfatepolymer composition application and solvent removal would be readilyapparent to a skilled artisan in manufacturing with suitable knowledgeof the substrate and solvent properties. During drying, the temperatureshould remain below 120° C. to prevent thermal decomposition of thethiosulfate groups in the thiosulfate polymer.

During the methods of use, the thiosulfate polymer compositions andarticles described herein can be exposed to suitable radiation, forexample having a wavelength of at least 200 nm and up to but less than725 nm, depending upon the spectral absorption of the electron-acceptingphotosensitizer component used in those embodiments.

A polymeric layer of the non-crosslinked thiosulfate polymer can beprovided and irradiated with the noted radiation to photochemicallyreact the thiosulfate polymer to provide a crosslinked polymer havingdisulfide groups in a predetermined pattern in the polymeric layer. Thepredetermined pattern can be provided using a mask layer, “digitalirradiation” (as used in digital printing), or flexographic printing.Irradiation can be focused in the foreground or background areas of thethiosulfate polymer layer, depending upon whether the thiosulfatepolymer layer is intended to function as a negative-working orpositive-working system. When a laser is used to irradiate thethiosulfate polymer layer, it is can be a diode laser providing aradiation of a desired wavelength, because of the reliability and lowmaintenance of diode laser systems, but gas or solid state lasers canalso be used. The combination of power, intensity and exposure time forlaser imaging would be readily apparent to one skilled in the art.Irradiation efficiency can be improved when the thiosulfate polymerlayer is thicker or also comprises one or more electron-acceptingphotosensitizer components (as defined above), either as separatecompounds or as part of the thiosulfate polymer.

As noted above, the reactant thiosulfate group in the thiosulfatepolymer is capable of undergoing a chemical transformation upon exposureand one electron oxidation, thus causing the change in solubility in theexposed regions of the thiosulfate polymer layer. The exposed areas ofthe thiosulfate polymer are crosslinked through generated disulfidebonds while the areas outside of the predetermined pattern remainnon-crosslinked. The thiosulfate groups undergo a photo-induced electrontransfer reaction to ultimately form a product species, a process thatdefines the cross-linking event. With the product formation, there areaccompanying changes in solubility, surface energy, glass transitiontemperature, and other optical properties such as refractive index,fluorescence properties, or absorption spectrum. New chemical bonds, forexample disulfide bonds, are formed between individual reactant moietiesthat results in a change in solubility.

Irradiation energy can be varied depending upon the thickness of thethiosulfate polymer layer, the concentration of thiosulfate groups inthe irradiated thiosulfate polymer(s), the concentration of anelectron-accepting photosensitizer component, the energy level of theirradiation, and other factors that would be readily apparent to oneskilled in the art. For example, useful laser irradiation with awavelength of at least 200 nm to and including 1200 nm can be carriedout using energy of at least 0.01 mJ/cm².

After the irradiation and formation of crosslinked polymer havingdisulfide bonds, the thiosulfate polymer layer can be washed with asuitable solvent (such as an aqueous solution) to remove thenon-crosslinked thiosulfate polymer while leaving the crosslinkedpolymer in the predetermined pattern. Water is a convenient solvent forremoving (developing) the non-crosslinked thiosulfate polymer but otheraqueous solutions are also useful, and they can be used at temperatureor heated up to and below the boiling point of the aqueous solvent.

The remaining crosslinked thiosulfate polymer (with disulfide bonds) canthen be treated with a suitable disulfide-reactive material. The mostimportant reaction of disulfide bonds is their cleavage, for exampleusing a reduction reaction. A variety of reductants can be used. Inbiochemistry, thiols such as mercaptoethanol (ME) or dithiothreitol(DTT) can be used as reductants. In organic synthesis, hydride agentsare typically employed for scission of disulfides, such as borohydride.Alkali metals and certain transition metals such as gold, silver, andcopper also cleave disulfide bonds. Such reactions can be used toselectively deposit silver, gold, or copper metals onto crosslinkedpolymers (having disulfide bonds) to make conductive patterns.

For example, the crosslinked thiosulfate polymer (with disulfide bonds)can be treated with a metal or metal salt that is reactive with thedisulfide bonds. Examples of such metals and metal salts include but arenot limited to, silver, gold, copper, nickel and iron, or salts thereof.Mixtures of metals or metal salts could be used. The treated crosslinkedthiosulfate polymer can then be used to pattern conductive coatings,pattern surface energy modulation, and pattern bioreactivity.

In some embodiments, metal can be sequestered in the thiosulfate polymercomposition after the polymeric layer is washed to removenon-crosslinked thiosulfate polymer. The remaining crosslinkedthiosulfate polymer in the thiosulfate polymer layer can be treated witha metal ion solution to incorporate ions of the metal in the thiosulfatepolymer layer areas comprising the crosslinked polymer. Metal ionsuseful for this purpose include but are not limited to, gold, silver,nickel, and copper ions, and can be supplied in a suitable aqueoussolution (also include metal ion dispersions). The incorporated metalions are reacted (reduced) to form nanoparticles of metal, and the metalnanoparticles can be electroless plated to obtain a coating of the metalin the predetermined pattern.

Yet another method relates to the hairdressing industry in which shapedhair (for example, human hair that has been shaped by a hairdresser) istreated or contacted with the thiosulfate polymer composition comprisinga thiosulfate polymer and an electron-accepting photosensitizercomponent having spectral absorption of up to and including 1200 nm. Thethiosulfate polymer composition used in this method is typically in anaqueous solvent so it can be readily applied to shaped hair for asuitable period of time and washed or rinsed out when the treatment iscompleted. The thiosulfate polymer composition can be applied to all oronly portions of the customer's shaped hair. This treatment of hair issometimes known in the art as “setting” or “fixing” hair.

Once the thiosulfate polymer composition has been applied to the shapedhair, the contacted shaped hair (portion of shaped hair to which thecomposition has been applied) can be exposed to suitable radiation toprovide disulfide groups in the thiosulfate polymer that are reactivewith protein in the contacted shaped hair. Such radiation is typicallyavailable from fluorescent or incandescent light sources.

In general, a skilled hairdresser would know how to choose suitable timeand temperature conditions to achieve the desired properties in theshaped hair of a customer. The shaped and treated hair can then be driedas is common in this industry.

Thus, in some other embodiments, the thiosulfate polymer composition canbe used to shape hair in a hair treatment. Thus, a method for shapinghair comprises:

transforming hair into shaped hair,

contacting the shaped hair with a composition comprising a thiosulfatepolymer of this invention having spectral absorption of up to andincluding 1200 nm, as described herein, and

exposing the contacted shaped hair with radiation to provide disulfidegroups in the thiosulfate polymer that are reactive with protein in thecontacted shaped hair.

For example, contacting the shaped hair can be carried out for at least0.5 minute and up to and including 20 minutes at a temperature of atleast 20° C. Other details for shaping hair with the thiosulfate polymercomposition would be readily apparent to one skilled in the art asdescribed in various publications directed to shaping hair, such as inU.S. Pat. No. 5,071,641 (noted above) and U.S. Pat. No. 5,424,062 (notedabove) the disclosures of which are incorporated herein.

The non-crosslinked thiosulfate polymer can be washed out of the shapedhair at a later time using any aqueous solution including a shampoo orconditioner.

For treating shaped hair, the thiosulfate polymer composition canadditionally contain any or all of the following components commonlyused in the hairdressing industry such as various protein dispersions,emulsifying agents, swelling agents (such as propylene glycol monomethylether), pH adjusting compounds, buffers, cosmetic agents (such asperfumes) lanolin derivatives, and thickening agents. For example, U.S.Pat. No. 5,242,062 (noted above) describes various additives useful inhair treating compositions in Columns 4 and 5, which disclosure isincorporated herein by reference.

The thiosulfate polymer composition that is useful for treating shapedhair can be provided in diluted or concentrated solutions or dispersions(emulsions), as well as creams, gels, or pastes. The compositions can bedelivered from bottles, pressurized aerosol cans, or any other suitablecontainer.

Methods for Applying and Imaging Thiosulfate Polymer Compositions

The methods of the present invention can be carried out in several waysto provide articles. For example:

1) A thiosulfate polymer composition can be applied to a suitablesubstrate;

2) The thiosulfate polymer composition coating can be then dried at from40 to 50° C. for at least 1 and up to and including 60 minutes;

3) The dried coating can be then exposed to radiation at an appropriatewavelength through a mask for an appropriate length of time (time ofexposure is determined by the extinction coefficient of theelectron-accepting photosensitizer component being used and thickness ofthe coating); and

4) The thiosulfate polymer composition in the unexposed areas of thecoating can be washed away, if desired, using an aqueous solution suchas plain water and the thiosulfate polymer composition that is removedcan be reused.

In some embodiments, metals can be deposited onto an imaged thiosulfatepolymer composition coating as the metal will deposit only in imagedareas. There are multiple ways to achieve selective area deposition of ametal.

One method can comprise:

Applying a thiosulfate polymer composition to a suitable substrate;

Drying the coating at from 40 to 50° C. for at least 1 and up to andincluding 60 minutes;

Exposing the dried thiosulfate polymer composition coating to radiationof an appropriate wavelength through a suitable mask for an appropriatelength of time (time of exposure is determined by extinction coefficientof the electron-accepting photosensitizer component being used andthickness of the coating);

Optionally washing the dried and exposed thiosulfate polymer compositioncoating with water or another aqueous solution to wash away thiosulfatepolymer composition in unexposed (non-imaged) areas to obtain an imageon the substrate; and the thiosulfate polymer composition that is washedaway can be reused;

Applying a conductive metal precursor salt solution to the exposed(imaged) areas on the substrate;

Adding a reducing agent to the substrate;

Optionally washing the exposed (imaged) areas on the substrate withwater or another aqueous solution; and

Depositing a suitable metal (for example from a dispersion) on exposed(imaged) areas on the substrate.

Another method comprises:

Coating a thiosulfate polymer composition onto a substrate;

Drying the thiosulfate polymer composition coating at from 40 to 50° C.for at least 1 and up to and including 60 minutes;

Exposing the dried coating to radiation of an appropriate wavelengththrough a mask for an appropriate length of time (time of exposure isdetermined by extinction coefficient of the electron-acceptingphotosensitizer component being used and thickness of the driedcoating);

Washing the dried coating with water or another aqueous solution to washaway thiosulfate polymer composition in the unexposed (non-imaged) areasto obtain an image on the substrate, and the thiosulfate polymercomposition that is washed away from the unexposed (non-imaged) areascan be reused;

Dipping the imaged substrate into or applying a metal nanoparticlecontaining solution; and

Optionally, washing the substrate with an aqueous solution so that metalnanoparticles are deposited only on the imaged (exposed) areas on thesubstrate.

In yet another embodiment, the method can include:

Coating a thiosulfate polymer composition onto a substrate;

Drying the thiosulfate polymer composition coating at from 40 to 50° C.for at least 1 and up to and including 60 minutes;

Exposing the dried thiosulfate polymer composition to radiation ofappropriate wavelength through a mask for appropriate length of time(the time of exposure is determined by the extinction coefficient of theelectron-accepting photosensitizer component being used and thickness ofthe coating);

Washing the dried thiosulfate polymer composition with water or anotheraqueous solution to wash away thiosulfate polymer composition in theunexposed (non-imaged) areas to obtain an image on the substrate, andthe thiosulfate polymer composition that is washed away from theunexposed (non-imaged) areas can be reused.

Dipping or contacting the imaged substrate with a conductive metalprecursor salt solution for an appropriate length of time; and

Washing the imaged substrate with a solution of a reducing agent so thatmetal nanoparticles are formed only in the imaged areas on thesubstrate.

Also provided is a method for electroless plating using the thiosulfatepolymer composition. Currently, electroless metal plating treatment canbe used to form a conductive coating film on an insulating object (forexample, an insulative layer). The electroless metal plating treatmentcan be carried out through a procedure having the following steps.

A conditioning step can be carried out using various surfactants toclean a substrate surface and to enable the surface to carry charges. Acatalyst-coating step can be carried out using a tin/palladium colloidbath. An activation step can be then carried out using hydrofluoric acidor another strong acid to activate the catalyst colloid that is adsorbedon the substrate surface. Electroless metal plating can then be carriedout using a plating bath containing a reducing agent such as formalin.When the substrate for the electroless metal plating treatment is aprinted circuit board for example, carrying a pattern, the pattern canbe formed with various methods, such as, but not limited to, thesubtractive method, semi-additive method, and full-additive method.

Other methods, such as primer treatment using palladium or silvercatalyst can also be used. In the primer treatment, a metal catalyst isintroduced into a resin material containing solvent and inorganicfiller. The resin material is coated onto a substrate to form a resinfilm containing a catalyst. Then, electroless metal plating is carriedout to form a conductive film. The primer treatment is mainly used on aplastic surface for the purpose of electromagnetic interference (EMI)shielding.

In the semiconductor field, sputtering and chemical vapor deposition(CVD) are more commonly used for the formation of a conductive layer andthe manufacturing technology has been established.

Moreover, a technology of introducing an organic metal salt withcatalytic activity into a resin material and then forming a conductingfilm with the resin material is disclosed in U.S. Pat. No. 5,059,242(Firmstone et al.) and has been used in the process of electrodeformation.

In electroless metal plating processes, the insulating resin material inthe printed circuit board and semiconductor device is first treated withdry etching or by using an agent such as permanganic acid to generate arough surface and to improve wettability. Then, electroless copperplating or electroless nickel plating can be conducted to form aconducting layer on the surface of the resin material.

However, it is very difficult to introduce a carboxyl group or ahydroxyl group into the resin matrix of a highly reliable insulatingresin material. The carboxyl group or hydroxyl group may reduce thereliability of the insulating resin material. As a result, theconducting layer formed through electroless metal plating has lowadhesive strength to the surface of the insulating resin material.Moreover, for the materials not suitable for generating these anchoringgroups, such as glass or ceramics to improve the attachment of a metalconductive layer, the metal conductive layer formed through electrolessmetal plating will also have low adhesive strength to the surface.

In the process of forming a conductive layer on a base material,currently the surface of the base material is first treated with oxygenplasma and then the conductive layer is formed with sputtering.Moreover, a conductive layer with the required thickness can be formedby this method by further electrolytic metal plating. However, althoughsputtering is a standard method for the formation of a thin layer, theprocess of sputtering usually takes a long period of time and the metaltarget is expensive. Therefore, the cost of the sputtering process isrelatively high.

On the other hand, the method for the formation of a conductive layerwith an organic metal salt uses a resinate compound of palladium,silver, or platinum. Such compound can be dissolved in water or anorganic solvent and the substrate to be coated is dipped into thesolution to form a coating layer of the resinate compound. Then, thermaldecomposition of the resinate compound generates a metal thin layer onthe substrate to be coated. Finally, electroless or electrolytic metalplating can be carried out to form a conductive layer. By using thismethod, however, the metal coating layer obtained has poor uniformity.In fact, the metal powder is simply attached to the surface of thesubstrate to be coated and the attachment is not very strong. In orderto solve the problem, a paste is prepared by introducing the metalresinate into a synthetic resin material, which is then coated on thesubstrate to form a uniform coating layer. The paste is widely used tofill holes on printed circuit boards and form electrodes on LCD throughscreen printing.

However, the conducting paste is not suitable for semiconductors andsemiconductor packages as well as other purposes requiring a highreliability. Moreover, it is very difficult to form fine lines throughscreen printing of the paste. In other words, when using an organicmetal salt in the formation of electronic devices, a paste can be firstprepared by introducing an organic metal salt to a synthetic resinmaterial and coating it onto a substrate through screen printing,followed by sintering to convert the organic metal salt to thecorresponding metal. In this process, the sintering temperature must behigher than the thermal decomposition temperature of the organic metalsalt (at least 300° C.) to remove the synthetic resin material.Therefore, when the synthetic resin material is completely removed, onlythe metal pattern remains. However, when the method is used in theformation of semiconductor packages, since the base body ofsemiconductor packages is made of a composite material of epoxy resinreinforced with glass fiber, the high temperature used in the sinteringstep will cause thermal damage, such as deformation or cracks, on thebase body. In addition, since the synthetic resin material is completelyremoved in the sintering step, various defects, such as pinholes or wirebreakage can be generated in the metal pattern obtained after sintering.In order to avoid these problems, a paste with a high metal content canbe used. More specifically, when using a paste containing a goldresinate to form a gold wire, the gold content in the paste must be ashigh as 25 weight % and the sintering temperature about 500° C. In otherwords, the sintering step in the coating method will cause severe damageto the substrate to be coated. In order to form a metal pattern with ahigh reliability, the content of the expensive metal in the paste shouldbe increased significantly, resulting in high production costs.

A purpose of this invention is to provide unique thiosulfate polymersand composition after imaging step that forms an organic functionalitywhere metal nanoparticles can be selectively absorbed. In a separatestep, these metal centers can act as seed sites for electroless metalplating.

The electroless metal plating method can include any commonly usedelectroless metal plating for depositing a metal selected from copper,nickel, gold, tin, zinc, silver, and cobalt as well as an alloy of thesemetals. There is no special limitation on the metal, plating bath, andplating conditions used in the electroless metal plating treatment.

The metal element used can be determined based on the electroless metalplating treatment. Any metal element can be used for the purpose as longas the metal element is able to provide a catalytic activity of metaldeposition suitable for electroless metal plating. Examples of thecatalytic metal element include but are not limited to, palladium,silver, platinum, rhodium, indium, and ruthenium. In consideration ofproduction cost and plating efficiency, tin or silver is particularlyuseful as the catalytic metal element for electroless metal plating of acopper, nickel, or nickel alloy.

For example, a method can comprise:

Providing a photolithographic pattern-forming thiosulfate polymercomposition as a coating in a multilayered integral body that comprises:(a) a substrate; (b) a photosensitive layer formed on one surface of thesubstrate (a), the photosensitive layer formed from the thiosulfatepolymer composition;

Exposing the thiosulfate polymer coating provided above to actinicradiation;

Optionally washing away the thiosulfate polymer coatings from the firsttwo steps using an aqueous solution (such as water); and

Dipping the thiosulfate polymer coating remaining from the prior step ina nanoparticle solution.

The present invention provides at least the following embodiments andcombinations thereof, but other combinations of features are consideredto be within the present invention as a skilled artisan would appreciatefrom the teaching of this disclosure:

1. A non-crosslinked polymer comprising, in random order: (a) recurringunits comprising pendant thiosulfate groups, and (b) recurring unitscomprising an electron-accepting photosensitizer component.

2. A non-crosslinked thiosulfate polymer comprising thiosulfate groupsand electron-accepting photosensitizer component arranged in the samerecurring units.

3. The non-crosslinked polymer of embodiment 1, wherein the (a)recurring units comprise at least 1 mol % and up to and including 99 mol%, and the (b) recurring units comprise at least 1 mol % and up to andincluding 99 mol %, based on the total recurring units in thenon-crosslinked polymer.

4. The non-crosslinked polymer of embodiment 1 or 3, wherein the (a)recurring units comprise at least 15 mol % and up to and including 90mol %, and the (b) recurring units comprise at least 10 mol % and up toand including 85 mol %, based on the total recurring units in thenon-crosslinked polymer.

5. The non-crosslinked polymer of any of embodiments 1 to 4, furthercomprising, in random order, additional (c) recurring units, in anamount of at least 0.1 mol %, based on the total recurring units in thenon-crosslinked polymer.

6. The non-crosslinked polymer of any of embodiments 1 to 5, furthercomprising, in random order, (c) recurring units derived from one ormore acrylates, methacrylates, acrylamides, methacrylamides, styrenemonomers, or other vinyl monomers.

7. The non-crosslinked polymer of any of embodiment 5 or 6, wherein the(c) recurring units comprise a pendant charged group.

8. The non-crosslinked polymer of any of embodiments 5 to 7, wherein the(c) recurring units comprise a pendant carboxy, carboxylate, phospho,phosphonate, phosphate, sulfo, sulfonate, or sulfite group

9. The non-crosslinked polymer of any of embodiments 1 to 8, wherein theelectron-accepting photosensitizer component is present in an amount ofat least 0.1 mol % and up to and including 10 mol %, in relation to themolar amount of thiosulfate groups present in the non-crosslinkedpolymer.

10. The non-crosslinked polymer of any of embodiments 1 to 9, whereinthe electron-accepting photosensitizer component has been derived froman organic photosensitizer N-containing heterocyclic compound.

11 The non-crosslinked polymer of any of embodiments 1 to 10, whereinthe electron-accepting photosensitizer component has been derived fromthe group of compounds consisting of cyanoaromatic compounds, aromaticanhydrides, aromatic imides, condensed pyridinium salts, pyrylliumsalts, and quinones.

12. The non-crosslinked polymer of any of embodiments 1 to 11 that has aglass transition temperature of at least 20° C. and up to and including250° C.

13. The non-crosslinked polymer of any of embodiments 1 to 12 comprisingpendant sodium or potassium thiosulfate groups.

14. A thiosulfate polymer comprising a polyester, polyamide,polyurethane, polycarbonate, or polyether backbone and pendantthiosulfate groups.

The following Examples are provided to illustrate the practice of thisinvention and are not meant to be limiting in any manner.

Synthesis 1: Preparation of Poly(vinyl benzyl thiosulfate sodiumsalt-co-methyl methacrylate)

A representative thiosulfate polymer useful in the practice of thepresent invention was prepared as follows:

Vinyl benzyl chloride (10 g, 0.066 mol), methyl methacrylate (26.23 g,0.262 mol), and AIBN (1.08 g, 7 mmol) were dissolved 180 ml of toluene.The resulting solution was purged with dry nitrogen and then heated at65° C. overnight. After cooling the solution to room temperature, it wasdropwise added to 2000 ml of methanol. The resulting white powderycopolymer was collected by filtration and dried under vacuum at 60° C.overnight. 1H NMR analysis indicated that the resulting copolymercontained 30 mol % of recurring units derived from vinyl benzylchloride.

A sample of this copolymer (18 g) was dissolved in 110 ml ofN,N-dimethyl formamide (DMF). To this solution was added sodiumthiosulfate (9 g) and 20 ml of water. Some polymer precipitated out. Thecloudy reaction mixture was heated at 70° C. for 24 hours. After coolingto room temperature, the hazy reaction mixture was transferred to adialysis membrane and dialyzed against water. A small amount of theresulting polymer solution was freeze dried for elemental analysis andthe rest was stored and used as a solution. Elemental analysis indicatedthat all the benzyl chloride groups in the copolymer were converted tosodium thiosulfate salt to provide a thiosulfate polymer useful in thepresent invention.

Synthesis 2: Preparation ofN-Butyl-N′-[2-(ethoxy-2-acrylate)ethyl]-1,4,5,8-naphthalenetetracarboxylicdiimide

A representative ethylenically unsaturated monomer useful to providethiosulfate polymers of the present invention was prepared as follows:

Step 1—Synthesis of the monopotassium salt (half anhydride), 1-potassiumcarboxylate-8-carboxylic acid naphthalene-4,5-dicarboxylic anhydride

A 12-liter, four-neck round bottom flask fitted with a mechanicalstirrer and a condenser was charged with potassium hydroxide (454 g,7.60 mol) and water (6 liters), followed by the addition of1,4,5,8-naphthalenetetracarboxylic dianhydride (462 g, 1.72 mol). Thereaction mixture was stirred for 1 hour and a clear solution resulted.Phosphoric acid, 85% (613 g 5.2 mol) in water (900 ml) was added over 45minutes, the reaction solution was stirred overnight, and the resultingsolid product was collected by filtration (yield close to 100%.) Thespectral data were consistent with its assigned structure.

Step 2—Synthesis of monoimide,naphthalenetetracarboxylic-1,8-N-butylimide-4,5-anhydride

A 12-liter, four-neck round bottom flask fitted with a mechanicalstirrer and a condenser was charged with the monopotassium salt fromStep 1 (169.2 g, 0.52 mol) and water (5 liters) to give a milkybrown-colored suspension. Butyl amine (240 g, 3.12 mol) was added all atonce and a clear amber-colored solution was formed. The reactionsolution was heated to 90-95° C. for 1 hour. Concentrated hydrochloricacid (690 ml) dissolved in 700 ml of water was added dropwise to the hotreaction solution and heating was continued for 2 hours. During theaddition, the temperature did not exceed 95° C. Heat was removed and thereaction was allowed to stir overnight at room temperature. Theresulting precipitate was collected on a glass frit to give 150 g of thedesired product at 90% yield. Spectral data were consistent with theassigned compound structure.

Step 3—Synthesis of diimide,N-butyl-N′42-(2-hydroxyethoxy)-ethyl]-1,4,5,8-naphthalenetetracarboxylicdiimide

A 12-liter, four-neck round bottom flask fitted with a mechanicalstirrer and a condenser was charged with naphthalene butylimidemonoanhydride (434 g, 1.4 mol) from Step 2, 2-(2-aminoethoxyethanol (230g, 2.2 mol), and N-methyl pyrrolidone (1.2 liters). The reactionsolution was heated to 140-150° C. for 3 hours. The reaction solutionwas then allowed to cool for 30 minutes and the reaction flask wasfilled with methanol and a pink-colored solid precipitated. The reactionsolution was stirred overnight and the resulting solid was collected ona glass frit to give 522 g of crude product (90% yield). Purificationwas carried out using dichloromethane on a silica gel column, providing313 g of product (54% yield). The spectral data were consistent with theassigned compound structure.

Step 4—Coupling of naphthalene bisimide alcohol with acryloyl chloride,N-butyl-N′-[2-(ethoxy-2-acrylate)ethyl]-1,4,5,8-naphthalenetetracarboxylicdiimide with acyloyl chloride

A 5-liter, four-neck round bottom flask fitted with a mechanicalstirred, condenser and a nitrogen inlet was charged with the hydroxylether naphthalene butyl bisimide of Step 3 (246 g, 0.6 mol) andtriethylamine (73 g, 0.72 mol, 100 ml) in dichloromethane (2 liters).Acryloyl chloride (63 g, 0.7 mol, 57 ml) in dichloromethane (DCM, 150ml) was added dropwise, solubilizing the reactants and the reactionsolution was stirred at room temperature overnight. The reactionsolution was washed with 5% hydrochloride acid (200 ml), forming anemulsion. Methanol was added to break up the emulsion. The organicproducts were washed with water and dried over magnesium sulfate. Theresulting product was purified on silica column using ligroin/DCMmixture at 1/1 then increasing to 100% DCM to elute the product. Thespectral data were consistent with the assigned compound structure.

Synthesis 3: Preparation of 1,8-Naphthalimidohexyl Acrylate

A representative ethylenically unsaturated monomer useful to providethiosulfate polymers of the present invention was prepared as follows:

Step 1—Synthesis of 1,8-Naphthalimidohexanol

A 200 ml round bottom flask fitted with condenser, nitrogen inlet, andstirring magnet was charged with 1,8-naphthalic anhydride (10 g, 50.5mmole), 6-amino-1-hexanol (6 g, 51.0 mmole), and 150 ml ofN-methyl-2-pyrrolidone. The reaction mixture was warmed to 140° C. for20 hours. The reaction mixture was then cooled and poured into excessice water. A resulting brown precipitate was filtered and recrystalyzedfrom heptane to give 5 g of a tan colored solid (30% yield). Thespectral data were consistent with assigned compound structure.

Step 2—Synthesis of 1,8-Naphthalimidohexyl acrylate

A 200 ml 3-neck round flask with a nitrogen inlet, and stirring magnetwas charged with the 1,8-naphthalimidohexanol (2.1 g, 7.1 mmole) and 60ml of anhydrous dichloromethane.

Once dissolved, triethylamine (0.9 g, 9.2 mmole) was added. To thisstirring mixture was slowly added acryloyl chloride (0.8 g, 9.2 mmole).The reaction mixture was allowed to stir at room temperature for 24hours. The reaction mixture was washed once with 10% HCl, then withwater and dried over magnesium sulfate, and the solvent was removed invacuo to provide a yellow semisolid. The resulting crude product waspurified by running it through column of silica with dichloromethane toelute the final product. The spectral data were consistent with theassigned compound structure.

Synthesis 4: Preparation of Poly(2-hydroxy-2-thiosulfate sodium saltpropyl methacrylate-co-methyl methacrylate

The procedure of Synthesis 1 was followed using glycidyl methacrylate(18.2 g, 0.128 mol), methyl methacrylate (30.0 g, 0.300 mol), 2,2%azobis(2-methylbutyronitrile) (0.82 g, 0.004 mol), and 192 ml oftoluene. The reaction temperature was 70° C. 1H NMR analysis indicatedthat the resulting precursor polymer contained 35 mol % of recurringunits derived from glycidyl methacrylate Analysis by size exclusionchromatography (SEC) indicated a weight average molar mass of 45,800(polystyrene standards)

The desired thiosulfate polymer was prepared as described for Synthesis1 using 30.0 g of precursor polymer, 140 ml of DMF, 16.8 g of sodiumthiosulfate, and 28 ml of water. The temperature of the reactionsolution was 70° C. for 24 hours. The thiosulfate polymer glasstransition temperature was determined to be 107.5° C. by DifferentialScanning Calorimetry (DSC).

Inventive Example 1 Preparation of Poly(vinyl benzyl thiosulfate sodiumsalt-co-methylmethacrylate-co-N-butyl-N′-[2-(ethoxy-2-acrylate)ethyl]-1,4,5,8-naphthalenetetracarboxylicdiimide)

The procedure of Synthesis 1 was followed using vinyl benzyl chloride(4.2 g, 0.027 mol), methyl methacrylate (8.5 g, 0.085 mol), the noteddiimide (1.1 g, 0.002 mol), 2,2′-azobis(2-methylbutyronitrile) (0.33 g,0.002 mol), and 47 ml of toluene. The reaction temperature was 70° C. 1HNMR analysis indicated that the resulting precursor polymer contained 30mol % of recurring units derived from vinyl benzyl chloride. Analysis bysize exclusion chromatography (SEC) indicated a weight average molarmass of 17,800 (polystyrene standards).

The desired thiosulfate polymer was prepared as described in Synthesis 1using 1.35 g of precursor polymer, 50 ml of DMF, 1.5 g of sodiumthiosulfate, and 10 ml of water. The temperature of the reactionsolution was 90° C. for 8 hours. The thiosulfate polymer glasstransition temperature was determined to be 99.8° C. by DifferentialScanning calorimetry (DSC).

Inventive Example 2 Preparation of Poly(vinyl benzyl thiosulfate sodiumsalt-co-methyl methacrylate-co-acrylicacid-co-N-butyl-N′-[2-(ethoxy-2-acrylate)ethyl]-1,4,5,8-naphthalenetetracarboxylicdiimide)

The procedure of Synthesis 1 was followed using vinyl benzyl chloride(8.2 g, 0.053 mol), methyl methacrylate (8.5 g, 0.085 mol), acrylic acid(8.5 g, 0.119 mol), the diimide (2.3 g, 0.005 mol),2,2′-azobis(2-methylbutyronitrile) (0.76 g, 0.004 mol), and 90 ml ofdioxane. The reaction temperature was 70° C. ¹H NMR analysis indicatedthat the resulting precursor polymer contained 30 mol % of recurringunits derived from vinyl benzyl chloride. Analysis by size exclusionchromatography (SEC) indicated a weight average molar mass of 41,600(polystyrene standards).

The desired thiosulfate polymer was prepared as described in Synthesis 1using 26.1 g of precursor polymer, 285 ml of DMF, 8.5 g sodiumthiosulfate, and 57 ml of water. The temperature of reaction was held at90° C. for 8 hours. The glass transition temperature of the resultingthiosulfate polymer was determined to be 195° C. by DifferentialScanning calorimetry (DSC).

Inventive Example 3 Preparation of Poly(vinyl benzyl thiosulfate sodiumsalt-co-acrylicacid-co-N-butyl-N′-[2-(ethoxy-2-acrylate)ethyl]-1,4,5,8-naphthalenetetracarboxylicdiimide)

The procedure of Synthesis 1 was followed using vinyl benzyl chloride(7.3 g, 0.048 mol), acrylic acid (15.0 g, 0.21 mol), the diimide (1.9 g,0.005 mol), 2,2′-azobis(2-methylbutyronitrile) (0.76 g, 0.004 mol), and73 ml of dioxane. The reaction temperature was 70° C. 1H NMR analysisindicated that the resulting precursor polymer contained 31 mol % ofrecurring units derived from vinyl benzyl chloride. Analysis by sizeexclusion chromatography (SEC) indicated a weight average molar mass of21,400 (polystyrene standards).

The desired thiosulfate polymer was prepared as described in Synthesis 1using 20.0 g of precursor polymer, 250 ml of DMF, 6.5 g sodiumthiosulfate, and 50 ml of water. The reaction temperature was 90° C. for8 hours to provide the desired thiosulfate polymer that had a glasstransition temperature of 200° C. as determined by DSC.

Inventive Example 4 Preparation of Poly(vinyl benzyl thiosulfate sodiumsalt-co-methyl methacrylate-co-1,8-naphthalimidohexyl acrylate)

The procedure of Synthesis 3 was followed using vinyl benzyl chloride(3.5 g, 0.023 mol), methyl methacrylate (7.7 g, 0.077 mol), the imide(0.5 g, 0.001 mol), 2,2′-azobis(2-methylbutyronitrile) (0.29 g, 0.002mol), and 40 ml of toluene. 1H NMR analysis indicated that the desiredprecursor polymer contained 34 mol % of recurring units derived fromvinyl benzyl chloride, and analysis by size exclusion chromatography(SEC) indicated a weight average molar mass of 25,800 (polystyrenestandards).

The desired thiosulfate polymer was prepared as described in Synthesis 1using 8.0 g of precursor polymer, 40 ml of DMF, 3.9 g of sodiumthiosulfate, and 8 ml of water. The reaction temperature was held at 90°C. for 8 hours to provide the desired thiosulfate polymer that had aglass transition temperature of 111° C. as measured by DSC.

Inventive Example 5 Preparation of Poly(vinyl benzyl thiosulfate sodiumsalt-co-methyl methacrylate-co-acrylic acid-co-1,8-naphthalimidohexylacrylate)

The procedure of Synthesis 1 was followed using vinyl benzyl chloride(3.0 g, 0.02 mol), methyl methacrylate (3.6 g, 0.036 mol), acrylic acid(3.0 g, 0.04 mol), the imide (0.4 g, 0.001 mol),2,2′-azobis(2-methylbutyronitrile) (0.28 g, 0.002 mol), and 30 ml ofdioxane. 1H NMR analysis indicated that the resulting precursor polymercontained 33 mol % of vinyl benzyl chloride, and analysis by SECindicated a weight average molar mass of 45,200 (polystyrene standards).

The desired thiosulfate polymer was prepared as described in Synthesis 3using 4.2 g of the precursor polymer, 22.5 ml of DMF, 2.1 g of sodiumthiosulfate, and 4.5 ml of water. The reaction temperature was held at90° C. to provide the desired thiosulfate polymer that had a glasstransition temperature of 119° C. as determined by DSC.

Comparative Example 1 Imaging Thiosulfate Polymer Coating

To 1 ml of an 8 weight % solution of poly(vinyl benzyl thiosulfatesodium salt-co-methyl methacrylate) (prepared as described inSynthesis 1) in water, was added 1 ml of tetrahydrofuran. The resultingcomposition was stirred and then spin-coated onto a glass plate (as asubstrate) at 1000 rpm. The composition coating was protected from UVand blue light at all times. The composition coating was then dried for5 minutes on a hot plate at 50° C. The dry thickness of the coated layerwas measured as described in Inventive Example 6, and found to be 0.8μm. The coated layer was exposed to light using a mercury lamp (EXFOActicure® spot curing system) through a mask for 10 seconds and thenwashed with water, followed by washing with acetone. All thiosulfatepolymer in the coated layer was washed away, and no image was detectedon the substrate. This example demonstrates that using a compositioncomprising only the thiosulfate polymer is ineffective to provide animageable article.

Use Example 1 Demonstration of Photoinduced Electron Transfer

To 1 ml of a 2 weight % solution of poly(vinyl benzyl thiosulfate sodiumsalt-co-methyl methacrylate-co-acrylicacid-co-N-butyl-N′-[2-(ethoxy-2-acrylate)ethyl]-1,4,5,8-naphthalenetetracarboxylicdiimide) (prepared in Inventive Example 5) in water, 1 ml oftetrahydrofuran was added and the solution was then spin-coated onto aglass plate support at 1000 rpm. The resulting coating was protectedfrom UV and blue light at all times, and dried for 5 minutes on a hotplate at 50° C. Absorption spectra of the coating were recorded beforeand after exposure to light. After exposure to light, the characteristicabsorption spectrum of naphthalenediimide radical anion (compared with achemically generated authentic spectrum) was observed. Formation ofnaphthalene diimide radical anion was concomitant withphoto-crosslinking as evidenced by a change in solubility of thecoating.

These results show that the thiosulfate polymer composition wasphotocrosslinked by photoinduced electron transfer to an electronacceptor.

Use Example 2 Photopatterning Thiosulfate Polymer Composition Coating

To 1 ml of a 2 weight % solution of poly(vinyl benzyl thiosulfate sodiumsalt-co-methyl methacrylate-co-acrylicacid-co-N-butyl-N′-[2-(ethoxy-2-acrylate)ethyl]-1,4,5,8-naphthalenetetracarboxylicdiimide) (prepared as described above in Inventive Example 4) in water,1 ml of tetrahydrofuran was added and the composition was spin-coatedonto a glass plate substrate at 1000 rpm. The coating was protected fromUV and blue light at all times, and was then dried for 5 minutes on ahot plate at 50° C. The dried composition coating was exposed to lightusing a Hg lamp through a mask for 6 seconds and then washed with water,followed by washing with acetone. The exposed areas of the compositioncoating on the glass plate substrate were rendered insoluble forming animage of the mask, whereas thiosulfate polymer composition in theunexposed areas of the dried coating was washed away.

These results show that the thiosulfate polymer compositions can be usedto prepare a photoresist useful for forming an image.

Use Example 3 Selective Area Deposition of Metal Nanowires onThiosulfate Polymer Composition

Silver nanowires were prepared using a standard polyol procedure asdescribed in U.S. Patent Application Publication 2011/0174190 (Sepa etal.), the disclosure of which is incorporated herein by reference.

Following three solutions were prepared:

Solution 1: A mixture of 6 grams of silver nitrate and 37 grams ofpropylene glycol in a beaker was stirred in the dark for about 6 hours.One half of Solution 1 was used for the initial and main additions. Theother half of the solution was kept in the dark to be used for the finalslow addition of silver nitrate during the second day of the reaction.

Solution 2: A mixture of 1.18 grams of tetrabutylammonium chloride wasdissolved in 10.62 grams of propylene glycol.

Solution 3: In a 1 liter, three-neck flask, a mixture of 7.2 grams ofpoly(vinyl pyrrolidone) and 445 grams of propylene glycol was heated toabout 90° C. Once the solution had stabilized at 90° C., it was purgedwith argon for 5 minutes. Then, 0.6% of Solution 1 was added into thereaction vessel and stirred for 10 seconds, followed by the addition ofSolution 2. After 4 minutes of allowing the seed reaction to begin,49.4% of Solution 1 was added to the reaction over the course of 45seconds, and the reaction was maintained at about 90° C. for 15 hours.All of these steps were carried out in vessels that were wrapped withaluminum foil to prevent exposure to light. After 15 hours of heating,the remaining 50% of Solution 1 was added slowly over the course of 4hours using a syringe pump. The reaction was allowed to continue for anadditional hour at which point heating was stopped and 100 ml ofdeionized water were added.

The whole crude reaction solution was allowed to settle for about 4days. The supernatant was silvery in color with a slight yellow tingeindicating a high concentration of Ag nanowires. The sediment wassilvery without a yellow tinge. The sediment was re-suspended indeionized water and viewed at 100× magnification using an oil immersionlens optical microscope. The resulting images showed a large populationof silver nanowires with some nanoparticles. The solution was then takenthrough a second settling process.

A thiosulfate polymer composition patterned coating was prepared in thefollowing manner:

An 8 weight % solution of poly(vinyl benzyl thiosulfate sodiumsalt-co-methyl methacrylate-co-1,8-naphthalimidohexyl acrylate)(prepared in Invention Example 4) in water was spin-coated on apolyethylene terephthalate substrate at 1000 rpm. The coating wasprotected from UV and blue light at all times, and then dried for 5minutes on a hot plate at 50° C., followed by exposure to light usingthe Hg lamp through a mask for 10 seconds, and the washed with water.The exposed areas of the dry composition coating on the glass platesubstrate were rendered insoluble forming an image of the mask, whereascomposition coating in the unexposed areas was washed away.

The patterned composition coating was immersed in a 1 weight % solutionof the silver nanowires in water for 1 minute and then thoroughly washedwith water. High resolution images of the patterned composition coatingclearly showed selective absorption of silver nanowires only in thephotopatterned areas.

These results demonstrate that the thiosulfate polymer compositions canbe used to form photoresists that can then be used to provide an imagefor selective deposition of silver nanowires.

Use Example 4 Formation of Conductive Patterned Coating UsingThiosulfate Polymer Composition Patterned Silver Wires

A silver metalizing bath was made by combining two separate baths. Onebath was a silver ion solution, while the other bath was a reducingagent solution. These two baths are denoted below them as Solutions Aand B, respectively.

Solution A:

Silver nitrate (0.817 g) was dissolved in 0.64 ml of ammonium hydroxideand then diluted by addition of 10 ml distilled water.

Rochelle's Salt Solution B:

Sodium potassium tartrate (Rochelle's salt, 2.86 g) and 0.205 grams ofmagnesium sulfate were dissolved in 10 ml of distilled water.

Plating Method:

Samples were immersed in a mixture of Solution A and B for 1 to 5minutes and subsequently washed with water.

Plating of Patterned Silver Nanowires:

The patterned coating of Use Example 2 was immersed in a silver platingsolution for 2 minutes and then washed with water. Metallic silverpattern was formed. Surface resistivity of the patterned coating wasmeasured to 10-15 Ω/□ using a four-point probe.

Use Example 5 Imaging Thiosulfate Polymer Containing Photosensitizer

To 1 ml of a 2 weight % solution of poly(vinyl benzyl thiosulfate sodiumsalt-co-methyl methacrylate-co-acrylicacid-co-N-butyl-N′-[2-(ethoxy-2-acrylate)ethyl]-1,4,5,8-naphthalenetetracarboxylicdiimide.) (prepared in Inventive Example 2) in water, was added 1 ml oftetrahydrofuran. The resulting composition was spin-coated onto a glassplate substrate at 100 rpm. The composition coating was protected fromUV and blue light at all times. The composition coating was dried for 5minutes on a hot plate at 50° C. The composition coating was exposed tolight using a mercury lamp through a mask for 6 seconds and was thenwashed with water, followed by washing with acetone. The exposed regionsof the dry composition coating on glass plate substrate were renderedinsoluble forming an image of the mask, whereas the dry composition innon-exposed regions was washed away.

These results demonstrate that the thiosulfate composition can be usedto form an article that can be imaged to form a photoresist.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

1. A non-crosslinked polymer comprising, in random order: (a) recurringunits comprising pendant thiosulfate groups, and (b) recurring unitscomprising an electron-accepting photosensitizer component.
 2. Thenon-crosslinked polymer of claim 1, wherein the (a) recurring unitscomprise at least 1 mol % and up to and including 99 mol %, and the (b)recurring units comprise at least 1 mol % and up to and including 99 mol%, based on the total recurring units in the non-crosslinked polymer. 3.The non-crosslinked polymer of claim 1, wherein the (a) recurring unitscomprise at least 15 mol % and up to and including 90 mol %, and the (b)recurring units comprise at least 10 mol % and up to and including 85mol %, based on the total recurring units in the non-crosslinkedpolymer.
 4. The non-crosslinked polymer of claim 1, further comprising,in random order, (c) recurring units other than the (a) and (b)recurring units, which (c) recurring units comprise a pendant chargedgroup, the (c) recurring units being present in an amount of at least0.1 mol %, based on the total recurring units in the non-crosslinkedpolymer.
 5. The non-crosslinked polymer of claim 1, further comprising,in random order, (c) recurring units derived from one or more acrylates,methacrylates, acrylamides, methacrylamides, styrene monomers, or othervinyl monomers.
 6. The non-crosslinked polymer of claim 4, wherein the(c) recurring units comprise a pendant charged group.
 7. Thenon-crosslinked polymer of claim 4, wherein the (c) recurring unitscomprise a pendant carboxy, carboxylate, phospho, phosphonate,phosphate, sulfo, sulfonate, or sulfite group.
 8. The non-crosslinkedpolymer of claim 1, wherein the electron-accepting photosensitizercomponent is present in an amount of at least 0.1 mol % and up to andincluding 10 mol %, in relation to the molar amount of thiosulfategroups present in the non-crosslinked polymer.
 9. The non-crosslinkedpolymer of claim 1, wherein the electron-accepting photosensitizercomponent has been derived from an organic photosensitizer N-containingheterocyclic compound.
 10. The non-crosslinked polymer of claim 1,wherein the electron-accepting photosensitizer component has beenderived from the group of compounds consisting of cyanoaromaticcompounds, aromatic anhydrides, aromatic imides, condensed pyridiniumsalts, pyryllium salts, and quinones.
 11. The non-crosslinked polymer ofclaim 1 that has a glass transition temperature of at least 20° C. andup to and including 250° C.
 12. The non-crosslinked polymer of claim 1comprising pendant sodium or potassium thiosulfate groups.
 13. Athiosulfate polymer comprising a polyester, polyamide, polyurethane,polycarbonate, or polyether backbone and pendant thiosulfate groups. 14.A non-crosslinked thiosulfate polymer comprising thiosulfate groups andelectron-accepting photosensitizer component arranged in the samerecurring units.